Ecological correlates in Brazilian Amazonian anurans: implications for conservation

2013 ◽  
Vol 34 (2) ◽  
pp. 217-232 ◽  
Author(s):  
Selvino Neckel-Oliveira ◽  
Selvino Neckel-Oliveira ◽  
Ulisses Galatti ◽  
Selvino Neckel-Oliveira ◽  
Ulisses Galatti ◽  
...  

The objective of the present study is to identify the ecological characteristics of Amazonian frogs that would make them candidates for endangered species status, and to quantify correlations between body size and geographic distribution. The study included 180 species for which information was available on life history characteristics, including reproductive mode, aquatic larval development, primary larval habitat and adult microhabitat, and activity period. Species with aquatic development were classified in eight ecological groups based on a cluster analysis. Twenty-eight of the aquatic-developing species share a stream-based larval development stage with groups of endangered or vulnerable species from Australia and Central America. The Amazonian species have geographic ranges around five times larger than their Australian and Central American counterparts. The median clutch size and geographic range in aquatic-developing anuran species were 20 percent and 3.3 percent greater, respectively, than those of terrestrial-developing species. For both aquatic- and terrestrial-developing species, body size was positively associated with clutch size. Body size was also correlated with geographic range in aquatic-developing, but not in terrestrial species. Restricted geographic ranges and a lack of populations in protected areas were recorded in both groups. Most of these species occur in the southwestern Brazilian Amazon, which not only has poor coverage of protected areas, but is becoming increasingly threatened by ongoing economic development. The systematic monitoring of the region’s anurans and the creation of new conservation units should thus be of the highest priority.

2018 ◽  
Vol 48 (4) ◽  
pp. 304-310 ◽  
Author(s):  
Thaís Billalba CARVALHO ◽  
Ellen Cristina Monteiro de SOUZA ◽  
Jaquelinne PINHEIRO-DA-SILVA ◽  
Marle Angélica VILLACORTA-CORREA

ABSTRACT Brycon amazonicus is a native Amazonian fish that is important for aquaculture in South America. Larval mortality is high in this species in intensive breeding systems due to aggressiveness among larvae. The present study investigated experimentally the effects of body size heterogeneity on the aggressive behavior and survival of B. amazonicus during the early stages of larval development. Two treatments (larvae groups with homogeneous and heterogeneous body size) were evaluated throughout early larval stages tested at six time points: 12, 24, 36, 48, 60 and 72 hours after hatching (HAH). Two experiments quantified, respectively, aggressive interactions and mortality rates among larvae at each time point. The frequency of aggressive interactions exhibited by the less aggressive larvae in each replicate was higher in the homogeneous size treatment. Aggressiveness was higher at 12 HAH, decreasing thereafter, and increasing again at 72 HAH. The mortality rate significantly increased with the larval stage, and was higher in the homogeneous than in the heterogeneous sized groups. Our results showed that aggressiveness in B. amazonicus larvae is affected by size variability and larval development stage. This knowledge about larval behavior is important to develop measures to improve larval health and survival in intensive production systems for this species.


2010 ◽  
Vol 16 ◽  
pp. 117-141 ◽  
Author(s):  
S. Kathleen Lyons ◽  
Felisa A. Smith

Macroecology is a rapidly growing sub-discipline within ecology that is concerned with characterizing statistical patterns of species' abundance, distribution and diversity at spatial and temporal scales typically ignored by traditional ecology. Both macroecology and paleoecology are concerned with answering similar questions (e.g., understanding the factors that influence geographic ranges, or the way that species assemble into communities). As such, macroecological methods easily lend themselves to many paleoecological questions. Moreover, it is possible to estimate the variables of interest to macroecologists (e.g., body size, geographic range size, abundance, diversity) using fossil data. Here we describe the measurement and estimation of the variables used in macroecological studies and potential biases introduced by using fossil data. Next we describe the methods used to analyze macroecological patterns and briefly discuss the current understanding of these patterns. This chapter is by no means an exhaustive review of macroecology and its methods. Instead, it is an introduction to macroecology that we hope will spur innovation in the application of macroecology to the study of the fossil record.


2008 ◽  
Vol 86 (12) ◽  
pp. 1376-1388 ◽  
Author(s):  
M. C. Kiefer ◽  
M. Van Sluys ◽  
C. F.D. Rocha

The tropidurid lizard Tropidurus torquatus (Wied, 1820) has a set of populations inhabiting coastal sand dune habitats (“restinga”) along the eastern Brazilian coast. Despite its wide geographic range, there is no information about geographic variation in reproductive features among its populations. In the present study we compared some reproductive aspects of females in 10 coastal populations of T. torquatus, aiming to evaluate to what extension they vary geographically. The minimum size at maturity was relatively similar to most populations, but mean female body size had a considerable variation. Clutch size of almost all coastal populations of T. torquatus had little variation and was composed predominantly of two eggs. Interpopulational variation in the mean egg volume was relatively wide and strongly influenced by the variation in mean female body size. The data of the present study indicated that females of almost all coastal populations of T. torquatus produce, predominantly, clutches with two eggs and invest more energy in egg size instead of clutch size, probably as a consequence of morphological and environmental factors. The increased reproductive investment in egg size was confirmed by the values obtained for the relative clutch mass, which remained relatively constant along the coastal geographic distribution of T. torquatus.


2009 ◽  
Vol 276 (1661) ◽  
pp. 1469-1476 ◽  
Author(s):  
Shai Meiri ◽  
Tamar Dayan ◽  
Daniel Simberloff ◽  
Richard Grenyer

Evolutionary biologists have long been fascinated by both the ways in which species respond to ecological conditions at the edges of their geographic ranges and the way that species' body sizes evolve across their ranges. Surprisingly, though, the relationship between these two phenomena is rarely studied. Here, we examine whether carnivore body size changes from the interior of their geographic range towards the range edges. We find that within species, body size often varies strongly with distance from the range edge. However, there is no general tendency across species for size to be either larger or smaller towards the edge. There is some evidence that the smallest guild members increase in size towards their range edges, but results for the largest guild members are equivocal. Whether individuals vary in relation to the distance from the range edges often depends on the way edge and interior are defined. Neither geographic range size nor absolute body size influences the tendency of size to vary with distance from the range edge. Therefore, we suggest that the frequent significant association between body size and the position of individuals along the edge-core continuum reflects the prevalence of geographic size variation and that the distance to range edge per se does not influence size evolution in a consistent way.


2011 ◽  
Vol 101 (1-2) ◽  
pp. 61-64 ◽  
Author(s):  
Conrado A. B Galdino ◽  
Monique Van Sluys

We studied life history traits of females of the lizard Eurolophosaurus nanuzae (Rodrigues, 1981), an endemic species of rock outcrop habitats in southeastern Brazil. During October 2002 and 2003 we sampled three populations in sites that encompass the meridional portion of the geographic range of the species. Clutch size varied from one to three eggs, with most females carrying two eggs. Clutch size did not vary among populations, but was correlated to female body size. Only larger females produced clutches of three eggs. Females of the small-sized E. nanuzae produce eggs as large as those of medium-sized tropidurids, thus investing a considerable amount of energy to produce clutches resulting in high values of relative clutch mass.


2021 ◽  
Author(s):  
Yuxi Zhong ◽  
Chuanwu Chen ◽  
Yanping Wang

Abstract China is a country with one of the most species rich reptile faunas in the world. However, nearly a quarter of Chinese lizard species assessed by the China Biodiversity Red List are threatened. Nevertheless, to date, no study has explicitly examined the pattern and processes of extinction and threat in Chinese lizards. In this study, we conducted the first comparative phylogenetic analysis of extinction risk in Chinese lizards. We addressed the following three questions: 1) What is the pattern of extinction and threat in Chinese lizards? 2) Which species traits and extrinsic factors are related to their extinction risk? 3) How can we protect Chinese lizards based on our results? We collected data on ten species traits (body size, clutch size, geographic range size, activity time, reproductive mode, habitat specialization, habitat use, leg development, maximum elevation, and elevation range) and seven extrinsic factors (mean annual precipitation, mean annual temperature, mean annual solar insolation, normalized difference vegetation index (NDVI), human footprint, human population density, and human exploitation). After phylogenetic correction, these variables were used separately and in combination to assess their associations with extinction risk. We found that Chinese lizards with small geographic range, large body size, high habitat specialization, and living in high precipitation areas were vulnerable to extinction. Conservation priority should thus be given to species with the above extinction-prone traits so as to effectively protect Chinese lizards. Preventing future habitat destruction should also be a primary focus of management efforts because species with small range size and high habitat specialization are particularly vulnerable to habitat loss.


Paleobiology ◽  
2007 ◽  
Vol 33 (3) ◽  
pp. 455-468 ◽  
Author(s):  
Marcelo M. Rivadeneira ◽  
Pablo A. Marquet

AbstractWe assessed selective extinction patterns in bivalves during a late Neogene mass extinction event observed along the temperate Pacific coast of South America. The analysis of 99 late Neogene and Quaternary fossil sites (recorded from 7°S to 55°S), yielding ∼2800 occurrences and 118 species, revealed an abrupt decline in Lyellian percentages during the late Neogene–Pleistocene, suggesting the existence of a mass extinction that decimated ∼66% of the original assemblage. Using the late Neogene data set (n = 59 species, 1346 occurrences), we tested whether the extinction was nonrandom according to taxonomic structure, life habit, geographic range, and body size. Our results showed that the number of higher taxa that went extinct was not different than expected by random. At first sight, extinction was selective only according to life habit and geographic range. Nevertheless, when phylogenetic effects were accounted for, body size also showed significant selectivity. In general, epifaunal, small-sized (after phylogenetic correction), and short-ranged species tended to have increased probability of extinction. This is verified by strong interactions between the variables herein analyzed, suggesting the existence of nonlinear effects on extinction chances. In the heavily decimated epifaunal forms, survival was not enhanced by widespread ranges or larger body sizes. Conversely, the widespread and large-sized infaunal forms tended to have lower probability of extinction. Overall, the ultimate extinction of late Neogene bivalve species along the Pacific coast of South America seems to have been determined by a complex interplay of ecological and historical (phylogenetic) effects.


2012 ◽  
Vol 15 (1) ◽  
Author(s):  
José Augusto Leitão Drummond ◽  
José Luiz De Andrade Franco ◽  
Daniela De Oliveira

This is a second overview of the Brazilian conservation unit system for mid-2010. It updates author et al, 2009. It examines six dimensions of federal and state protected areas – age, numbers, types of units, absolute and average sizes, distribution by states and biomes, and degree of compliance with CBD-inspired goals. Major findings: (i) the system maintained a rapid growth rate; (ii) national parks and national forests are the most prominent units; (iii) distribution of units by region and biome remains unbalanced; (iv) state units grew remarkably over the last five years; (v) state units are biased towards sustainable use; (vi) sustainable use units grew more than fully protected units; (vii) Amazonia remains the most extensively protected biome; and (viii) quantitative goals of biome protection are closer to being reached. In 2010 Brazil held the fourth position globally in protected areas; it created the largest number of units between 2000 and 2010; it has the largest combined area of protected tropical formations. However, several regions and biomes remain under protected. 


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10868
Author(s):  
Beata Grzywacz ◽  
Piotr Skórka

Why do some species occur in small, restricted areas, while others are distributed globally? Environmental heterogeneity increases with area and so does the number of species. Hence, diverse biotic and abiotic conditions across large ranges may lead to specific adaptations that are often linked to a species’ genome size and chromosome number. Therefore, a positive association between genome size and geographic range is anticipated. Moreover, high cognitive ability in organisms would be favored by natural selection to cope with the dynamic conditions within large geographic ranges. Here, we tested these hypotheses in birds—the most mobile terrestrial vertebrates—and accounted for the effects of various confounding variables, such as body mass, relative brain mass, and geographic latitude. Using phylogenetic generalized least squares and phylogenetic confirmatory path analysis, we demonstrated that range size is positively associated with bird genome size but probably not with chromosome number. Moreover, relative brain mass had no effect on range size, whereas body mass had a possible weak and negative effect, and range size was larger at higher geographic latitudes. However, our models did not fully explain the overall variation in range size. Hence, natural selection may impose larger genomes in birds with larger geographic ranges, although there may be additional explanations for this phenomenon.


2004 ◽  
Vol 13 (5) ◽  
pp. 439-444 ◽  
Author(s):  
N. Olifiers ◽  
M. V. Vieira ◽  
C. E. V. Grelle
Keyword(s):  

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